基于二次混频DPT的LFMCW雷达多目标检测和参数估计

针对LFMCW雷达中高速加速运动目标的检测问题，该文提出一种二次混频DPT处理方法。利用三角线性调频信号的调频对称性，采用上、下调频差拍信号二次混频的方法消除目标高速运动导致的跨距离单元走动现象。按距离单元进行的DPT处理可获得目标加速度和初始速度的估计。进一步重点研究了多目标存在时的参数估计问题。分析了多目标交叉项的特点，得出了一次交叉项形成有效干扰以及二次交叉项出现的条件。借助于Clean算法的思想，通过依次检测并剔除能量最强目标，有效解决了多目标参数估计问题。给出了多目标处理的主要步骤。仿真结果验证了该文方法及结论的有效性。

Detection and Parameter Estimation of Multi-targets Based on Secondary Mixing Combined DPT Method in LFMCW Radar

To solve the detection problem of high-speed accelerating targets in LFMCW (Linear Frequency- Modulated Continuous Wave) radar, a secondary mixing combined DPT (Discrete Polynomial-phase Transform) method is proposed. Utilizing the modulation symmetry of tri-LFMCW signals, up-sweep beat signal is secondary mixed with down-sweep one to eliminate MTRC (Migration Through Range Cell) induced by the high-speed. And DPT processing in terms of range cell leads to the estimation of acceleration and initial velocity. Furthermore, parameter estimation of multi-targets is emphasized. By analyzing the characteristics of the cross terms, the conditions for first order cross terms forming effective interfere and for second order cross terms emerging are derived, respectively. Resorting to Clean algorithm, multi-targets can be dealt with successfully, which detects and removes the strongest target for the current time. Processing steps of multi-targets cases are given. Simulation results testify the effectiveness of the method and the conclusions.